Conveying Fluid Research Articles

Nonlinear Vibration Analysis of Single-Walled Carbon Nanotube Conveying Fluid in Slip Boundary Conditions Using Variational Iterative Method

In this paper, nonlinear dynamic behaviour of the carbon nanotube conveying fluid in slip boundary conditions is studied using the variation iteration method. The developed solutions are used to investigate the effects of various parameters on the nonlinear vibration of the nanotube. The results indicate that an increase in the slip parameter leads to a decrease in the frequency of vibration and the critical velocity, while the natural frequency and the critical fluid velocity increase as the stretching effect increases. Also, as the nonlocal parameter increases, the natural frequency and the critical velocity decreases. The analytical solutions help to have better insights and understand the relationship between the physical quantities of the problem.

Analysis of Flow-induced Vibration of Fluid Conveying Pipe with Elastic Support

Analysis of Flow-induced Vibration of Fluid Conveying Pipe with Elastic Support

Acoustic Nanowave Absorption through Clustered Carbon Nanotubes Conveying Fluid

Absorption of acoustic nanowave in specific frequency region is important for the design of acoustic filter. This paper puts forward a meta material model made up of fluid-conveying carbon nanotubes (CNT), which can absorb acoustic nanowave in a given frequency range by adjusting the lengths and fluid velocities of themselves. Absorption coefficients are calculated out through the combination of the finite element method with the theoretical model, which are 0.4∼0.55 relating to different fluid velocities for the crossing-distributed model. Comparisons are made between the crossed model and the aligned one, which prove that the CNT forest with crossed distribution is more effective in acoustic wave absorption.

Effect of Uniformly Distributed Tangential Follower Force on the Stability of Rotating Cantilever Tube Conveying Fluid

In this paper, the Euler-Bernoulli beam model is used to predict the structural instability of rotating cantilever tubes conveying fluid and subjected to uniform distributed tangential compressive load. The governing equation of motion and boundary conditions of the system are derived using the Hamilton's principle. Then, Galerkin method is applied in order to transform the resulting equation into a general eigenvalue problem. The present analysis is validated by comparing the results with those available in literature. Furthermore, the model is utilized to elucidate the stability characteristics of the system for different conditions.

Ultrasonic Guided Wave Method For Crack Detection In Buried Plastic Pipe

Plastic pipe are widely used in many fields for the fluid or gaseous product conveyance but basic components of a plastic material made it very sensitive to damage, which requires techniques for detecting damage reliable and efficient. Ultrasonic guided wave is a sensitive method based on propagation of low-frequency excitation in solid structures for damage detection. Ultrasonic guided wave method are performed to investigate the effect of crack to the frequency signal using Fast Fourier Transform (FFT) analysis. This paper researched to determine performance of ultrasonic guided wave method in order to detect crack in buried pipeline. It was found that for an uncrack pipe, FFT analysis shows one peak which is the operating frequency by the piezoelectric actuator itself while the FFT analysis for single cracked pipe shows two peak which is the operating frequency by the piezoelectric actuator itself and the resultant frequency from the crack. For multi cracked pipe, the frequency signal shows more than two peak depend the number of crack. The results presented here may facilitate improvements in the accuracy and precision of pipeline crack detection.

Variational Principles for Vibrating Carbon Nanotubes Conveying Fluid, Based on the Nonlocal Beam Model

AbstractVariational principles are derived in order to facilitate the investigation of the vibrations and stability of single and double-walled carbon nanotubes conveying a fluid, from a linear time-dependent partial differential equation governing their displacements. The nonlocal elastic theory of Euler-Bernoulli beams takes small-scale effects into account. Hamilton’s principle is obtained for double-walled nano-tubes conveying a fluid. The natural and geometric boundary conditions identified are seen to be coupled and time-dependent due to nonlocal effects.

Dynamic Response of the Pipe Conveying Fluid with the Pressure Pulsation

The dynamic response characteristic of the pipe conveying fluid was researched with the fluid pressure pulsation in this article. For some hydraulic power pipe system, formed the mathematic models and the transfer matrices of the main hydraulic elements based on the fluid network algorithm, deduced the calculation formulae of input-output pressure pulsation, gained the transitive relationship of the fluid flow pulsation and pressure pulsation, and then studied the pressure pulsation amplitude of the hydraulic power pipes with different working pressures. This study, which analyzed the dynamic response of the pipe conveying fluid and discussed the feasibility of increasing the working pressure, is valuable for the design and the application of the pipes conveying fluid.

Influence of Thermal and Longitudinal Magnetic Field on Vibration Response of a Fluid Conveying Double Walled Carbon Nanotube Embedded in an Elastic Medium

Influence of Thermal and Longitudinal Magnetic Field on Vibration Response of a Fluid Conveying Double Walled Carbon Nanotube Embedded in an Elastic Medium

Mathematica numerical simulation of peristaltic biophysical transport of a fractional viscoelastic fluid through an inclined cylindrical tube

This paper studies the peristaltic transport of a viscoelastic fluid (with the fractional second-grade model) through an inclined cylindrical tube. The wall of the tube is modelled as a sinusoidal wave. The flow analysis is presented under the assumptions of long wave length and low Reynolds number. Caputo's definition of fractional derivative is used to formulate the fractional differentiation. Analytical solutions are developed for the normalized momentum equations. Expressions are also derived for the pressure, frictional force, and the relationship between the flow rate and pressure gradient. Mathematica numerical computations are then performed. The results are plotted and analysed for different values of fractional parameter, material constant, inclination angle, Reynolds number, Froude number and peristaltic wave amplitude. It is found that fractional parameter and Froude number resist the flow pattern while material constant, Reynolds number, inclination of angle and amplitude aid the peristaltic flow. Furthermore, frictional force and pressure demonstrate the opposite behaviour under the influence of the relevant parameters emerging in the equations of motion. The study has applications in uretral biophysics, and also potential use in peristaltic pumping of petroleum viscoelastic bio-surfactants in chemical engineering and astronautical applications involving conveyance of non-Newtonian fluids (e.g. lubricants) against gravity and in conduits with deformable walls.

Effect of a Viscoelastic Foundation on the Dynamic Stability of a Fluid Conveying Pipe

In this study, the natural frequency of a simply supported pipeline (hinged type) conveying one-dimension incompressible steady fluid flow set on viscoelastic foundation is investigated by using finite element analysis and the critical fluid velocity with different parameters such as stiffness and viscous coefficients of foundation are obtained. The foundation is simulated using the modified Winkler's model to introduce the effect of time dependent viscosity term. Some known results are confirmed and some new ones obtained. Two components of foundation, stiffness and viscosity, seemed to act on the critical flow velocity of the pipe in contrary trend. Where, increasing the foundation stiffness tended to increase the critical flow velocity in the pipe. While, increasing foundation viscosity attempted to decrease it. At some ranges of pipe length, the foundation viscosity effect seems to be more extreme. Increasing the fluid velocity leads to monotonic reduction in the system damping ratio. Two parameters, pipe length and fluid density which relate to the natural frequency of pipeline conveying fluid are studied in detail and the results indicate that the effect of Coriolis force on natural frequency is become more effective by increasing pipe length and fluid density besides increasing fluid flow velocity.

411 内部流による弾性送水管の空間運動に関する実験(OS09-2 機械力学(1)機械の動的解析と設計問題,オーガナイズドセッション9:「機械力学(1)機械の動的解析と設計問題」)

411 内部流による弾性送水管の空間運動に関する実験(OS09-2 機械力学(1)機械の動的解析と設計問題,オーガナイズドセッション9:「機械力学(1)機械の動的解析と設計問題」)

Subharmonic Bifurcations and Transition to Chaos in a Pipe Conveying Fluid under Harmonic Excitation

Subharmonic Bifurcations and Transition to Chaos in a Pipe Conveying Fluid under Harmonic Excitation

Stability of Subharmonic Oscillations in a Pipe Conveying Fluid under Harmonic Excitation

The existence and stability of subharmonic oscillations in a two end-fixed fluid conveying pipe whose base is subjected to a harmonic excitation are investigated. A Galerkin approach is utilized to reduce the equation of motion to a second order nonlinear differential equation. The conditions for the existence of subharmonic oscillations are given by using Melnikov method. The stability of subharmonic oscillations is discussed in detail by using action-angle variable and averaging method. It is shown that the velocity of fluid plays an important role in the stability of subharmonic oscillations.

Stability of Subharmonic Oscillations in a Pipe Conveying Fluid under Harmonic Excitation

The existence and stability of subharmonic oscillations in a two end-fixed fluid conveying pipe whose base is subjected to a harmonic excitation are investigated. A Galerkin approach is utilized to reduce the equation of motion to a second order nonlinear differential equation. The conditions for the existence of subharmonic oscillations are given by using Melnikov method. The stability of subharmonic oscillations is discussed in detail by using action-angle variable and averaging method. It is shown that the velocity of fluid plays an important role in the stability of subharmonic oscillations.

Subharmonic Bifurcations and Transition to Chaos in a Pipe Conveying Fluid under Harmonic Excitation

The subharmonic and chaotic behavior of a two end-fixed fluid conveying pipe whose base is subjected to a harmonic excitation are investigated. Melnikov method is applied for the system, and Melnikov criterions for subharmonic and homoclinic bifurcations are obtained analytically. The numerical simulations (including bifurcation diagrams, maximal Lyapunov exponents, phase portraits and Poincare map) confirm the analytical predictions and exhibit the complicated dynamical behaviors.

Study on Hydromechanics with Critical Instability Flowrate of Two Ends Supported Pipe Conveying Fluid

The expression of vertical vibration mode-function of fluid conveying pipe supported elastically on two ends was derived from the boundary conditions of similarly supported beam. The dynamic stability of pipe conveying fluid with the same supporting conditions was invesigated and the expression of its critical instability flowrate was obtained. The effects of fluid pressure and axial force of pipe section on critical instability flowrate were calculated and analyzed based on the eigenequation. The numerical results showed that the critical instability flowrate were proportional to axial drawn force, but proportional conversely to fluid pressure and axial pressed force of pipe section. The critical instability flowrate of fluid conveying pipe varied greatly with its supporting conditions. In order to improve its value at engineering application, the axial pressed force of pipe section should be avoided.

The Natural Characteristics of Fluid Conveying Pipe under Different Supporting Conditions

The natural characteristics of fluid conveying pipe with its ends under different supporting conditions were investigated. The expression of vertical vibration mode-function of pipe beam was derived from the boundary conditions of similarly supported beam. The effect of different supporting elastic coefficient, fluid pressure, flowrate, and axial force of pipe section on its natural characteristics was calculated and analyzed based on the eigenequation of motion. The numerical computation results showed that its natural frequency was proportional to elastic supporting coefficient and axially pressed force of pipe section, but was proportional conversely to fluid flowrate, fluid pressure and axially sectional drawn force of pipe. The natural frequency of different modes can be coupled with each other, the primarily mode and secondly mode would change either. In order to improve the natural frequency of fluid conveying pipe, the elastically constrained coefficients should be extended and the axially pressed force of pipe section should be avoided.

Terahertz Wave Propagation in a Nanotube Conveying Fluid Taking into Account Surface Effect.

In nanoscale structure sizes, the surface-to-bulk energy ratio is high and the surface effects must be taken into account. Surface effect plays a key role in accurately predicting the vibration behavior of nanostructures. In this paper, the wave behaviors of a single-walled carbon nanotube (CNT) conveying fluid are studied. The nonlocal Timoshenko beam theory is used and the surface effect is taken into account. It is found that the fluid can flow at a very high flow velocity and the wave propagates in the terahertz frequency range. The surface effects can significantly enhance the propagating frequency. This finding is different from the classical model where the surface effect is neglected.

Study on the Influence of Gravity Factor on Parametric Resonance of Pipe Conveying Fluid

The averaging method has been applied to calculate the critical conditions of parametric resonance instability of the first order mode shape of clamped-clamped and pinned-pinned pipes conveying fluid. The influence of gravity factor on parametric resonance of pipe conveying fluid, with different supporting forms and different flow velocity, has been studied based on the comparison results of gravity factor being considered and neglected. It is concluded that gravity factor has a greater influence on parametric resonance region of pinned-pinned pipe than the one of clamped-clamped pipe, and, at a higher flow velocity, gravity factor is more influential to both pinned-pinned pipe and clamped- clamped one.

0818 内部流による弾性送水管の非線形横振動 (複数の固有振動が不安定となる場合)(OS05-4 機械力学(2)音と振動の解析・制御技術,オーガナイズドセッション 5:「機械力学(2)音と振動の解析・制御技術」)

0818 内部流による弾性送水管の非線形横振動 (複数の固有振動が不安定となる場合)(OS05-4 機械力学(2)音と振動の解析・制御技術,オーガナイズドセッション 5:「機械力学(2)音と振動の解析・制御技術」)